Due to reduced cabin cross-sections, executive and smaller commercial airplanes typically are designed without cargo compartments below the cabin floor. Instead, the cabin sub-floor space available in such aircraft is typically used to house aircraft system components such as, environmental (air-conditioning) ducts, hydraulic tubing, wiring harnesses, control cables and the lie. In general, the structures needed to support the loads of the cabin floor have typically been formed of separate beam and support post components made of light weight sheet metal (aluminum). These separate structures are then connected, e.g., by rivets, so as to fabricate the sub-flooring support system. As a result, a large number of individual flooring system components each having separate part numbers must be inventoried and assembled thereby aggravating fabrication time and weight.
It is known, for example, from WO 2007/122096 to provide an aircraft flooring system having at least one central rail mounted to a rigid aircraft structure, at least two lateral rails placed on either side of the central rail and each being connected vertically to the aircraft structure by a vertical connecting rod but being free transversely. Floor panels are place between two adjacent central rails so that transverse stresses to which the lateral rails are subjected pass through the floor panels as far as the central rails.
Integrated aircraft flooring structures have been proposed in WO 2006/102090 which include top and bottom layer skins and a structural core formed of a honeycomb composite material disposed between the skins.
It would therefore be highly desirable if aircraft cabin flooring structures could be integrated in a manner that would reduce the parts inventory and/or weight associated with conventional aircraft flowing systems. It is toward providing such needs that the present invention is directed.
Broadly, the structures, systems and methods disclosed herein provide a load-bearing aircraft flooring within an aircraft's fuselage. In especially preferred embodiments, load-supporting aircraft flooring systems will be provided with a longitudinally separated series of transverse bridges having an upper doubler flange which defines latitudinally separated upper openings, and a latitudinally separated series of beams which include an upper flange and a pair of separated depending web flanges received within respective upper openings of transverse bridges. The upper flanges and web flanges of the beams may thus be connected to the transverse bridges.
The transverse bridges may include latitudinally separated Y-shaped supports which define the upper openings thereof. According to certain embodiments, the Y-shaped supports include an upper fork region and a lower support post region. The lower support post region may define outwardly and downwardly divergent side edges. Additionally (or alternatively), the upper fork region may define outwardly and upwardly divergent side edges. The web flanges of the beams may have outwardly directed stiffener flanges at terminal ends thereof. Angle brackets may be provided to join the web flanges to the transverse bridges (e.g., by means of bolt assemblies, rivets and the like).
According to some embodiments, the beams will include opposed bridge fixation fingers protruding outwardly from the upper flange of the beam for joining the beams to a respective underlying one of the transverse bridges. Aircraft flooring panels may thus be connected to the beams, preferably by means of flooring fixation fingers protruding outwardly from the upper flange of the beams. Seat tracks for attaching aircraft seats and/or other interior aircraft structures/monuments are preferably fixed to the upper flanges of the beams coincident with its longitudinal axis.
A pair of longitudinally oriented angled side sills may be provided according to certain embodiments to attach the bridges to the aircrafts fuselage. Preferably, the side sills will have lower attachment fingers for attachment to respective ends of the transverse bridges and upper attachment fingers adapted for connection to structural components of an aircraft fuselage.
The transverse bridges, longitudinal beams and/or side sills are preferably formed of a fiber-reinforced composite material. Alternatively, one or each of such components may be formed of a light weight metal (e.g., aluminum).
An aircraft flooring system formed from a series of the transverse bridges and beams by positioning the bridges transversely relative to an aircraft fuselage, positioning the beams longitudinally relative to the aircraft fuselage such that the web flanges of the beams are received in respective ones of the upper openings of the bridges, and joining the bridges and beams to one another. Aircraft flooring panels may then be joined to the beams. The bridges may also be joined to structural components of the aircraft fuselage, e.g., by means of side sills as note briefly above.
These and other features and advantages will be better and more completely understood by referring to the following detailed description of exemplary non-limiting illustrative implementations in conjunction with the drawings.